barton gellman of "time" magazine and the "washington post." david sanger of the "new york times," and cbs news political director john dickerson. a lot to cover, but it's what we do on "face the nation." captioning sponsored by cbs from cbs news in washington, "face the nation" with bob schieffer. >> schieffer: and good morning again. well, we're getting more details this morning on why the government has closed those 22 american diplomatic posts across the middle east and north africa, and why they are taking so seriously the threat of a possible al qaeda attack. the travel warning that the state department issued last week for americans traveling overseas we're now told will remain in effect for the rest of this month. for the latest this morning, we're going toure cbs news homeland security security correspondent bob orr, who has been on this for all-- for a long, long time. bob, why are they taking this one so much more seriously than some of the things in the past? >> because this threat, bob, comes from the group from al qaeda, al qaeda